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<head>
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  <title>Document</title>
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<body>
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  <script>
    const input = document.querySelector('input')
    input.addEventListener('keyup', function (e) {
      if (e.keyCode === 190) {
        alert('不允许出现小数')
      }
      console.dir(e);
    })
  </script>
</body>

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